Sustainable shaft grounding with variable frequency drives

  Currents induced on motor shafts by variable speed drives (VFDs) can wreak havoc with motor bearings, shortening motor life dramatically and causing costly repairs. A reliable method of shaft grounding is essential to mitigate these currents and realise the full potential of VFDs. In the field of flow control, the potential for increased efficiency […]

Switchgear for power factor correction systems

  The importance of differentiating between various circuit types or capacitor assignments to inductive loads when implementing power factor correction (PFC). A differentiation is made between individual PFC and group PFC. With individual PFC, the capacitor is assigned individually or switched to a load. With group PFC, the power factor of a load group is […]

Clever pumping: making the water industry’s pumps intelligent

  Climate change, increasing water demands and the legal obligations of the EU’s Water Framework Directive are all making the water sector an attractive arena for technologies that can help reduce costs and contribute to reducing the effects of climate change. It is against this backdrop that the demand for intelligent process control equipment is […]

Maximising surge protection safety

  Servicing surge protection devices (SPDs) safely without impacting critical operations has traditionally been difficult but a new generation SPDs is solving this problem. Servicing traditional SPDs poses serious risks to maintenance personnel and mission-critical workloads. If the SPD has an internal disconnect, power on the line side of the disconnect continues to flow even […]

Circuit breaker design for safety in underground mining applications

  Circuit breaker applications in underground mining and recommended methods to maximise the effectiveness of these protective devices In mining, the underground assembly or power centre is engineered to transform and distribute electrical power brought underground. This assembly typically includes a medium-voltage incoming circuit breaker or switch with current-limiting fuse (see Fig 1). The device […]

Selection of AC induction motors for cement plant applications

The selection of AC induction motors for cement mill applications, with reference to fan, kiln and vertical mill applications. Cement plant applications present an immense matrix of application criteria to specify, design and build motors properly. Operating conditions Basic motor specifications begin with determining the motor nameplate horsepower (hp) and revolutions per minute (rpm). These […]

Clever pumping: making water industry’s pumps intelligent

  Climate change, increasing water demands due to global urbanisation, and the legal obligations of the EU’s Water Framework Directive are all making the water sector an attractive arena for technologies that can help reduce costs and contribute to reducing the effects of climate change. It is against this backdrop that the demand for intelligent […]

Improving motor efficiency

  Some 20% of the estimated 65% of industrial energy used by electric motors is lost by wasteful throttling mechanisms, making it essential to reduce the energy appetite of motors. Energy consumption by electric motors can be reduced in two main ways – efficient control of the speed at which they run, and making the […]

The energy efficiency of over-current protective devices

  A test programme to quantify energy losses in over-current protective devices (OCPDs) shows that switches and fuses are less energy-efficient compared with equivalent circuit breakers carrying the same load currents. The devices in an electrical distribution system are a critical part of the facility’s infrastructure. These devices include transformers, conductors and over-current protective devices. […]